import 'package:drift/drift.dart' show Value;
import 'package:flutter/material.dart';
import '../database/daos/month_dao.dart';
import '../database/database.dart';
import '../theme.dart';
import 'inline_edit_cell.dart';

/// Balance type labels and display order.
enum BalanceTypeLabel {
  credit('Credit', 0),
  loan('Loan', 1),
  mortgage('Mortgage', 2),
  personal('Personal', 3);

  final String label;
  final int value;
  const BalanceTypeLabel(this.label, this.value);
}

class TopBar extends StatelessWidget {
  final int remainingCents;
  final int bufferCents;
  final int eatingOutBudgetCents;
  final MonthPlan currentPlan;
  final List<MonthPlan> allMonths;
  final List<BillDefinition> bills;
  final MonthDao monthDao;
  final ValueChanged<int> onMonthSelected;
  final VoidCallback onCloneMonth;
  final ValueChanged<int> onDeleteMonth;
  final VoidCallback onSettingsTap;
  final VoidCallback onDataChanged;

  const TopBar({
    super.key,
    required this.remainingCents,
    required this.bufferCents,
    required this.eatingOutBudgetCents,
    required this.currentPlan,
    required this.allMonths,
    required this.bills,
    required this.monthDao,
    required this.onMonthSelected,
    required this.onCloneMonth,
    required this.onDeleteMonth,
    required this.onSettingsTap,
    required this.onDataChanged,
  });

  static const _monthNames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
  static const _fullMonthNames = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];

  @override
  Widget build(BuildContext context) {
    final bufferOk = remainingCents >= bufferCents;

    // Group outstanding by balance type
    final typeTotals = <int, int>{}; // balanceType → total cents
    final outstandingBills = <BillDefinition>[];
    for (final bill in bills) {
      if (bill.outstandingBalanceCents != null && bill.outstandingBalanceCents! > 0) {
        outstandingBills.add(bill);
        final bt = bill.balanceType ?? 0; // default to Credit
        typeTotals[bt] = (typeTotals[bt] ?? 0) + bill.outstandingBalanceCents!;
      }
    }
    final hasOutstanding = typeTotals.isNotEmpty;

    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
      decoration: const BoxDecoration(
        color: bgCard,
        border: Border(bottom: BorderSide(color: borderColor)),
      ),
      child: Row(
        children: [
          // Net Balance + Buffer
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const Text('NET BALANCE', style: TextStyle(fontSize: 11, color: textMuted, letterSpacing: 0.5)),
              Text(
                formatCents(remainingCents),
                style: TextStyle(
                  fontSize: 28,
                  fontFamily: monoFont,
                  fontWeight: FontWeight.w600,
                  color: remainingCents >= 0 ? accentGreen : accentRed,
                ),
              ),
              if (bufferCents > 0) ...[
                const SizedBox(height: 2),
                Container(
                  padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                  decoration: BoxDecoration(
                    color: bufferOk
                        ? accentGreen.withValues(alpha: 0.15)
                        : accentAmber.withValues(alpha: 0.15),
                    borderRadius: BorderRadius.circular(3),
                  ),
                  child: Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      IntrinsicWidth(
                        child: InlineEditCell.cents(
                          cents: bufferCents,
                          onSaved: (cents) async {
                            final clamped = cents < 0 ? 0 : cents;
                            await monthDao.updateMonthPlan(
                              currentPlan.id,
                              MonthPlansCompanion(bufferAmountCents: Value(clamped)),
                            );
                            onDataChanged();
                          },
                          style: TextStyle(
                            fontSize: 11,
                            fontFamily: monoFont,
                            color: bufferOk ? accentGreen : accentAmber,
                          ),
                          textAlign: TextAlign.left,
                        ),
                      ),
                      Text(
                        ' BUFFER: ${bufferOk ? "OK" : "LOW"} (${bufferOk ? "+" : ""}${formatCents(remainingCents - bufferCents)})',
                        style: TextStyle(
                          fontSize: 11,
                          fontFamily: monoFont,
                          color: bufferOk ? accentGreen : accentAmber,
                        ),
                      ),
                    ],
                  ),
                ),
              ],
            ],
          ),
          // Outstanding balances (clickable)
          if (hasOutstanding) ...[
            const SizedBox(width: 24),
            GestureDetector(
              onTap: () => _showOutstandingOverlay(context, outstandingBills),
              child: MouseRegion(
                cursor: SystemMouseCursors.click,
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text('OUTSTANDING', style: TextStyle(fontSize: 11, color: textMuted, letterSpacing: 0.5)),
                    const SizedBox(height: 4),
                    Row(
                      children: [
                        for (final bt in BalanceTypeLabel.values)
                          if (typeTotals.containsKey(bt.value)) ...[
                            if (bt.value > 0 && typeTotals.entries.where((e) => e.key < bt.value).isNotEmpty)
                              const SizedBox(width: 18),
                            Column(
                              crossAxisAlignment: CrossAxisAlignment.start,
                              children: [
                                Text(bt.label, style: const TextStyle(fontSize: 11, color: textDim)),
                                Text(
                                  formatCents(typeTotals[bt.value]!),
                                  style: const TextStyle(fontSize: 15, fontFamily: monoFont, color: accentAmber),
                                ),
                              ],
                            ),
                          ],
                      ],
                    ),
                  ],
                ),
              ),
            ),
          ],
          const Spacer(),
          Text(
            _fullMonthNames[currentPlan.month - 1],
            style: const TextStyle(fontSize: 24, fontWeight: FontWeight.w600, color: textPrimary),
          ),
          const SizedBox(width: 6),
          Text('${currentPlan.year}', style: const TextStyle(fontSize: 14, color: textMuted)),
          const SizedBox(width: 20),
          _buildMonthGrid(context),
          const SizedBox(width: 16),
          IconButton(
            icon: const Icon(Icons.settings, color: textMuted, size: 20),
            onPressed: onSettingsTap,
            padding: EdgeInsets.zero,
            constraints: const BoxConstraints(minWidth: 32, minHeight: 32),
          ),
        ],
      ),
    );
  }

  void _showOutstandingOverlay(BuildContext context, List<BillDefinition> outstandingBills) {
    final renderBox = context.findRenderObject() as RenderBox;
    final offset = renderBox.localToGlobal(Offset.zero);

    showDialog(
      context: context,
      barrierColor: Colors.transparent,
      builder: (ctx) => Stack(
        children: [
          // Dismiss on tap outside
          Positioned.fill(
            child: GestureDetector(
              onTap: () => Navigator.pop(ctx),
              behavior: HitTestBehavior.opaque,
            ),
          ),
          Positioned(
            left: offset.dx + 180,
            top: offset.dy + 60,
            child: _OutstandingOverlay(
              bills: outstandingBills,
              monthDao: monthDao,
              onDataChanged: () {
                onDataChanged();
                Navigator.pop(ctx);
              },
            ),
          ),
        ],
      ),
    );
  }

  bool _isFutureMonth(MonthPlan plan) {
    final now = DateTime.now();
    return plan.year > now.year || (plan.year == now.year && plan.month > now.month);
  }

  Future<void> _confirmClone(BuildContext context) async {
    final currentYearMonths = allMonths.where((m) => m.year == currentPlan.year).toList();
    final lastMonth = currentYearMonths.isNotEmpty ? currentYearMonths.last.month : currentPlan.month;
    final nextMonth = lastMonth == 12 ? 1 : lastMonth + 1;
    final nextMonthName = _fullMonthNames[nextMonth - 1];

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: bgCard,
        title: Text('Ready to start planning $nextMonthName?', style: const TextStyle(fontSize: 16, color: textPrimary)),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('No', style: TextStyle(color: textMuted))),
          TextButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('Yes', style: TextStyle(color: accentGreen))),
        ],
      ),
    );
    if (confirmed == true) onCloneMonth();
  }

  Future<void> _confirmDelete(BuildContext context, MonthPlan plan) async {
    final monthName = _fullMonthNames[plan.month - 1];
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: bgCard,
        title: Text('Delete $monthName ${plan.year}?', style: const TextStyle(fontSize: 16, color: textPrimary)),
        content: const Text('This cannot be undone.', style: TextStyle(fontSize: 13, color: textMuted)),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('No', style: TextStyle(color: textMuted))),
          TextButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('Yes, delete', style: TextStyle(color: accentRed))),
        ],
      ),
    );
    if (confirmed == true) onDeleteMonth(plan.id);
  }

  Widget _buildMonthGrid(BuildContext context) {
    final currentYearMonths = allMonths.where((m) => m.year == currentPlan.year).toList();
    final monthSet = currentYearMonths.map((m) => m.month).toSet();

    final rows = <List<Widget>>[];
    var currentRow = <Widget>[];

    for (final m in currentYearMonths) {
      final isCurrent = m.id == currentPlan.id;
      currentRow.add(_monthSquare(
        _monthNames[m.month - 1],
        active: true,
        current: isCurrent,
        onTap: () {
          if (isCurrent && _isFutureMonth(m)) {
            _confirmDelete(context, m);
          } else {
            onMonthSelected(m.id);
          }
        },
      ));
      if (currentRow.length == 4) {
        rows.add(currentRow);
        currentRow = [];
      }
    }

    final lastMonth = currentYearMonths.isNotEmpty ? currentYearMonths.last.month : 0;
    if (lastMonth < 12 && !monthSet.contains(lastMonth + 1)) {
      currentRow.add(_monthSquare('+', isAdd: true, onTap: () => _confirmClone(context)));
    }
    if (currentRow.isNotEmpty) {
      rows.add(currentRow);
    }

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: rows.map((row) {
        return Padding(
          padding: const EdgeInsets.only(bottom: 2),
          child: Row(children: row),
        );
      }).toList(),
    );
  }

  Widget _monthSquare(String label, {bool active = false, bool current = false, bool isAdd = false, VoidCallback? onTap}) {
    return GestureDetector(
      onTap: onTap,
      child: MouseRegion(
        cursor: SystemMouseCursors.click,
        child: Container(
          width: 38,
          height: 26,
          margin: const EdgeInsets.only(right: 3),
          decoration: BoxDecoration(
            color: current
                ? accentGreen.withValues(alpha: 0.3)
                : active
                    ? accentGreen.withValues(alpha: 0.1)
                    : Colors.transparent,
            borderRadius: BorderRadius.circular(4),
            border: Border.all(
              color: current ? accentGreen : active ? accentGreen.withValues(alpha: 0.4) : isAdd ? textDim : borderColor,
            ),
          ),
          alignment: Alignment.center,
          child: isAdd
              ? const Icon(Icons.add, size: 16, color: textDim)
              : Text(
                  label,
                  style: TextStyle(
                    fontSize: 11,
                    fontWeight: current ? FontWeight.w600 : FontWeight.normal,
                    color: current ? textPrimary : (active ? textMuted : textDim),
                  ),
                ),
        ),
      ),
    );
  }
}

/// Overlay listing bills with outstanding balances, allowing type assignment.
class _OutstandingOverlay extends StatelessWidget {
  final List<BillDefinition> bills;
  final MonthDao monthDao;
  final VoidCallback onDataChanged;

  const _OutstandingOverlay({
    required this.bills,
    required this.monthDao,
    required this.onDataChanged,
  });

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Colors.transparent,
      child: Container(
        width: 340,
        decoration: BoxDecoration(
          color: bgCard,
          border: Border.all(color: borderColor),
          borderRadius: BorderRadius.circular(6),
          boxShadow: [BoxShadow(color: Colors.black.withValues(alpha: 0.4), blurRadius: 12, offset: const Offset(0, 4))],
        ),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            const Padding(
              padding: EdgeInsets.fromLTRB(12, 10, 12, 6),
              child: Text('OUTSTANDING BALANCES', style: TextStyle(fontSize: 11, color: textMuted, letterSpacing: 0.5)),
            ),
            const Divider(color: dividerColor, height: 1),
            for (final bill in bills)
              _OutstandingBillRow(bill: bill, monthDao: monthDao, onDataChanged: onDataChanged),
          ],
        ),
      ),
    );
  }
}

class _OutstandingBillRow extends StatelessWidget {
  final BillDefinition bill;
  final MonthDao monthDao;
  final VoidCallback onDataChanged;

  const _OutstandingBillRow({
    required this.bill,
    required this.monthDao,
    required this.onDataChanged,
  });

  @override
  Widget build(BuildContext context) {
    final currentType = bill.balanceType ?? 0;

    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
      decoration: const BoxDecoration(
        border: Border(bottom: BorderSide(color: dividerColor, width: 0.5)),
      ),
      child: Row(
        children: [
          // Bill name + note
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  children: [
                    Text(bill.name, style: const TextStyle(fontSize: bodySize, color: textPrimary)),
                    if (bill.subtitle != null) ...[
                      const SizedBox(width: 6),
                      Flexible(
                        child: Text(
                          bill.subtitle!,
                          style: const TextStyle(fontSize: 11, color: textDim, fontStyle: FontStyle.italic),
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                    ],
                  ],
                ),
                Text(
                  formatCents(bill.outstandingBalanceCents ?? 0),
                  style: const TextStyle(fontSize: 11, fontFamily: monoFont, color: accentAmber),
                ),
              ],
            ),
          ),
          // Type selector chips
          Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              for (final bt in BalanceTypeLabel.values) ...[
                if (bt.value > 0) const SizedBox(width: 3),
                _typeChip(bt, currentType == bt.value),
              ],
            ],
          ),
        ],
      ),
    );
  }

  Widget _typeChip(BalanceTypeLabel bt, bool active) {
    return GestureDetector(
      onTap: () async {
        await monthDao.updateBill(
          bill.id,
          BillDefinitionsCompanion(balanceType: Value(bt.value)),
        );
        onDataChanged();
      },
      child: MouseRegion(
        cursor: SystemMouseCursors.click,
        child: Container(
          padding: const EdgeInsets.symmetric(horizontal: 5, vertical: 2),
          decoration: BoxDecoration(
            color: active ? accentAmber.withValues(alpha: 0.15) : Colors.transparent,
            border: Border.all(color: active ? accentAmber.withValues(alpha: 0.5) : borderColor),
            borderRadius: BorderRadius.circular(3),
          ),
          child: Text(
            bt.label,
            style: TextStyle(
              fontSize: 9,
              color: active ? accentAmber : textDim,
              fontWeight: active ? FontWeight.w600 : FontWeight.normal,
            ),
          ),
        ),
      ),
    );
  }
}